def graficarVectores(vecs, cols, alpha = 1):

    plt.axvline(x = 0, color = "grey", zorder = 0)
    plt.axhline(y = 0, color = "grey", zorder = 0)

    for i in range(len(vecs)):
        x = np.concatenate([[0,0], vecs[i]])
        plt.quiver([x[0]],
                    [x[1]],
                    [x[2]],
                    [x[3]],
                    angles = "xy", scale_units = "xy",
                    scale = 1,
                    color = cols[i],
                    alpha = alpha
                    )

plt.style.use("classic")
imagen = Image.open("/work/imagen_ejemplo_frida_bredesen.jpg")
plt.imshow(imagen)